I personally think the Thermapen is worth every penny for both accuracy and time. I don't have a Maverick PT-100 which is probably the next best alternative, but I can tell you that the Thermapen really shines in how fast it reads which also adds to its accuracy because you know what he see is the final temp. A couple of things you can do to increase the accuracy is one, when you insert it pull it back about halfway out again before you read it to ensure you not against a bone or influenced by grate temp, two calibrate it and adjust it for accuracy. The Thermapen allows you to actually make adjustments to the readings which is something most of the cheaper alternatives don't.
BTW - when it comes to steaks and the like, I never use a thermometer. I test them by touch
WSM, 99 & 09 Performers, 2-OTG, SJG mini WSM, Summit 420, Q100, Akorn, and Schwenkgrill